Pinterest

Launched in 2010, Pinterest is a fast-growing social networking site that operates like an online bulletin board.

Users are able to "pin" their favorite pictures and organize them in theme-based collections called "boards." Users can also like, comment on and re-pin other people’s images to their boards.

Pinterest is open to individual users as well as companies and brands. The site is particularly popular among women users.

The company is based in Palo Alto, Calif., and was founded by Evan Sharp, Ben Silbermann and Paul Sciarra. Some of the company's venture investors include Andreessen Horowitz, Bessemer Venture Partners and FirstMark Capital.